Maintenance And Daily Protection Of Submersible Pump
Apr 12, 2022
Protection of submersible pump
1. Electrical
(1) Check the operating voltage and DC current of submersible pump from time to time. The three-phase voltage measured by water pressure gauge shall be basically unified, and it shall be 340 ~ 420v. The three-phase DC current measured by clamp DC ammeter shall be basically unified, and it shall be 0.5 ~ 1 times of additional DC current.
(2) Regularly review the thermal insulation resistance of submersible pump to ground. After 4 ~ 6h of abnormal operation, stop the machine and measure the insulation resistance of motor winding to ground with a megger, which shall be greater than 0.5m Ω. For submersible pumps that have been out of service for a short time, such review should also be made before use.
(3) Before starting the machine, check whether the sharpness of the thermal relay and other shield installation operations are abnormal.
(4) Check the cable for damage. As for the oil immersed submersible electric pump, pay attention to the damage of the oil leakage of the electric pump to the cable insulation rubber.
2. Above machinery
(1) Review the mechanical seal condition of submersible pump from time to time. Open the oil hole screw and release a large amount of oil. If the oil contains moisture, indicate that the seal of the upper grinding block (or lower grinding block) has leaked water. Replace the sealing box and exit the new frozen oil. If there is a lack of oil in the oil hole or the oil quality is poor, fill up the oil (No. 5 or No. 10 mechanical oil, sewing oil or transformer oil) or replace it with new oil.
(2) For the submersible pump with new or replaced grinding block, the sealing plug of withered water shall be rotated after 50 hours of operation, and the leakage of oil (water) shall be reviewed. If < 5ml, the sealing deformity shall be indicated, and it can be used continuously. If > 5ml, the sealing plug shall be tightened after draining the oil (water), and the second review shall be conducted after 50 hours of continuous operation. If it is still > 5m1, the sealing problem shall be indicated. For the used submersible pump, the disclosure amount shall be reviewed once a month, which shall be less than 25ml, and can be used continuously after being drained.
(3) Check the vibration condition of the water pump motor, and the synchronous speed of the motor is N0 = 3000r / min, 1500r / min, 1000r / min and 750r / min, so as to ensure that the corresponding vibration value is δ ≤0.06mm、0.1mm、0.13mm、0.16mm。
(4) Regularly review the bearing condition of submersible pump. Check whether the bearing is short of oil, whether there is running inner ring or outer ring, and whether the bearing needs to be replaced (it is best to replace the bearing of water filled electric pump once a year).
3. Other above
(1) Always check whether the water inlet net cover of the submersible pump is blocked by weeds and dirt and whether the impeller is wound.
(2) The submersible pump that is unnecessary in a short time should be put forward to the port surface, cleaned and dried, and then placed upright in a dry and ventilated room for storage.
(3) After the submersible pump has operated for 1 ~ 2 years, the core pulling of the motor shall continue to be reviewed and cleaned. If there is any dirt, immerse the motor in 0.2% Haiou TX-10 or 105 soap powder solution, heat it to about 100 ℃ and stir the solution to slow down the dissolution of the dirt. After the dirt is removed for 1 ~ 2H, develop and marinate it with low-pressure tap water, remove the water beads, and dry it in the furnace at high temperature.
3、 Maintenance of submersible pump
1. Common faults, causes and solutions of submersible electric pump
2. Rewinding of motor rotor winding
(1) In order to prevent or reduce the insensitive rotation of the swivel caused by the disassembly error, before assembling the motor, mark the joint between the front and rear ends and the base with a accumulator, and disassemble it as it is after trimming.
(2) When removing the winding, pay attention to cover the iron core to prevent the silicon wafer from warping and shifting, and the appearance of slot tooth angle burrs. The better removal steps are: first cut the coil from one end with diagonal pliers, and then pull it out at the other end with pliers.
(3) The winding mold shall be made according to the required size to wind the coil, so as to ensure the outward clearance of the winding end and the insertion of the coil into the slot.
(4) The "three-dimensional method" shall be adopted for wire embedding, that is, after embedding one phase, another phase shall be embedded to make the end form a "three-dimensional": pay attention when embedding: ① the position of the first two "lifting handle" coils shall be appropriate to ensure that the rotor core will not be scratched when embedding other coils; ② Use less scribing board when drawing the bottom coil to avoid damaging the coil insulation; ③ Interphase insulating paper shall be inserted in place, and the two-phase coils shall be wide and leave; ④ For oil immersed and water filled motors, the coil in the slot (including the end) shall not be compacted, so that the oil (water) can be fixed to dissipate heat for the winding.
(5) Solve the problem of joint insulation. Peel off the sheath and coating at the joint, and remove the nominal paint layer and oxide layer of copper wire; Then, continue soldering by splicing, and remove sharp corners, burrs and residual welding fluid; Then half Pack 2 layers with polyethylene tape, half pack 6 layers with butyl self-adhesive tape stretched about twice (the joint shall be careful and seamless), and initially half Pack 2 layers with polyethylene adhesive tape or cesium fiber adhesive tape as mechanical cover.
(6) Keep dirty during disassembly. Carefully adjust the "limit screw" at the bottom to make the screw rotate freely, and tighten the locking screw nut. Install the end cover according to the original sealing position, and be careful not to damage the rubber sealing ring in the inner hole of the sealing box. When the whole body sealing box is disassembled, it can only be pushed in slightly without knocking.
4、Try to disassemble the motor
(1) Pneumatic attempt. Use 2kg / mm2 air pressure to check whether the "O" rubber sealing ring at the joint of each complete machine and the two sealing covers in the whole body sealing box are breathable. After that, add mechanical oil into the high and low covers.
(2) DC resistance. The resistance value of each phase winding of the rotor shall be within ± 2% of the error scale of the uniform value of three-phase winding resistance.
(3) Insulation resistance. It should be > 5m Ω at normal temperature.
(4) Mechanical review. When the electric pump is running, the tone of each element shall be abnormal.
(5) Shipboard attempt. The shipboard DC and shipboard loss under additional voltage are almost the same as that of the original motor. For the rarely used 2.2kW submersible electric pump, the shipboard DC is 1.8 ~ 2.5A, and the shipboard loss is less than 0.5KW.
(6) Load attempt. After running in water for 4h, the temperature rise of the motor shall be ≤ 75 ℃.
(7) Braking attempt. Tie the impeller and connect it to 100V phase exchange power supply. The DC value of each phase shall be within ± 10% of the uniform value of three-phase DC.